The present invention relates to a process and method for the joining of glass, particularly phosphate glass, using a solution at low, e.g. room temperature or temperatures below the glass transition point of the glasses to be joined. The present invention also relates to joined phosphate glasses, a solution for the bonding of phosphate glasses, and methods of employing joined phosphate glass (e.g. hybid or similar glass joints) in photonic applications, especially in laser and related applications.
Bonded glass is well known in the manufacture of various light transmitters, refractors, reflectors, and the like. Optical clarity, e.g. low loss at the bonded zone, is of high importance in various applications and various high temperature methods to obtain as high a quality joint as possible are known. High performance instruments or devices, especially optical devices, require a quality bonded joint to prevent optical loss.
For a bond""s quality to be ascertained, factors such as the precision of the bond, the bond""s mechanical strength, the bond""s optical, thermal, and chemical properties, as well as the simplicity of the bonding process are considered.
The present application relates to a glass composite formed from a first phosphate glass surface and a second phosphate glass surface, the composite having in between and in contact with each surface, a phosphorous-containing solution. In a preferred embodiment, the composite is formed from a first and second phosphate glass interface having in between and in contact with said interface a layer of cured phosphorus-containing aqueous solution. In yet another embodiment, the layer is a condensed phosphorus phase (e.g. a (Pxe2x80x94Oxe2x80x94P)n layer). The composites according to the present invention are preferably prepared by joining two phosphate glass substrates together by curing therebetween a phosphorus containing aqueous solution. The method according to the present invention includes bonding two phosphate glass surfaces by curing therebetween a phosphorus-containing aqueous solution. Hybrid glass joints according to the present invention find use in photonic devices including a phosphate glass component therein, such as laser sources, lossless splitters, etc.
A phosphate glass as used within this application means a glass where P2O5 is the primary glass forming component present, although other glass forming components SiO2, GeO2, P2O3 or conventional modifiers (e.g. Na2O, K2O) and intermediates (e.g. Al2O3) may be present in lesser quantity.
A phosphorous-containing solution as used within this application is to be construed as broadly encompassing suitable soluble phosphorous, e.g. phosphates, phosphites, and related phosphorous-containing species.
An object of the present invention is to provide a method for joining glass components at low temperature using a solution based technology.
An additional object of the invention is to provide enhanced structured phosphate glass composites without heat related defects (e.g. surface crystallization or warping).
An additional object of the invention is to provide an optically transparent phosphate glass composite.
An additional object of the invention is to provide an aqueous, phosphorus-containing solution as an adhesive for preparing mechanically strong and optically transparent joints between phosphate glasses.
An additional object of the invention is to provide improved hybrid photonic devices where active (lasing) phosphate glasses are joined to other active or passive (non-lasing) phosphate glasses.
An additional object of the invention is to provide acidic or basic phosphorus-containing solutions as adhesives for phosphate glass joining.
An additional object of this invention is to provide a method whereby an aqueous phosphorus-containing solution is used to form an optically transparent and mechanically strong joint between phosphate glasses at low temperaturexe2x80x94below the lowest glass transition temperature of the two glasses being joined.
An additional object of the present invention is to provide a method to form hybrid photonic devices, which contain various phosphate glass components joined in such a way that they are optically transparent.
A further object of the instant invention is to provide a method for joining phosphate glasses joined at room temperature by dissolution and condensation reactions.
A further object of the instant invention is to provide a composite glass with minimal defects caused by differences in the coefficient of thermal expansion of the components since they are joined at low temperatures.
A further object of the instant invention is to provide a process for the preparation of composite phosphate glass wherein the glass does not necessarily have to be ramped or quenched through any temperature range to form a rigid joint.
An additional object of the present invention is to provide a joining adhesive solution (e.g. the phosphorus-containing solution used to join the phosphate glasses) which is chemically similar to the glass.
A further object of the instant invention is to provide a phosphate glass to phosphate glass interface with low turbidity, and a transparent interface.
An additional object of the instant invention is to provide a composite glass joint which is optically transparent at the wavelengths commonly used for photonic systems utilizing wavelengths from 800 to 2500 nm.
An additional object of the instant invention is to provide a joined or bonded phosphate glass joint which is made at low (e.g. room) temperature and has sufficient mechanical strength to survive oil-based cutting, grinding and polishing.
An additional object of the instant invention is to provide a joined or bonded phosphate glass joint which is made at low (e.g. 25xc2x0 C.) temperature and has sufficient mechanical strength to survive water-based cutting, grinding and polishing after a heat treatment.
Finally, an additional object of the present invention is to provide a phosphate glass surface joint with no appreciable strain or birefringence around the interface.